• Journal of Environmental Health Sciences
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• v.19 no.3
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• pp.52-57
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• 1993

This study was carried out to investigate the air pollution in Hwasoon Nulitjae tunnel for two months, from August 1992 to September 1992. The total suspended particles were collected by high volume air sampler at inside and outside of Hwasoon Nulitjae tunnel, of which major water soluble component and heavy metalic element were analyzed. Size distribution and respirable mass fraction of aerosol at inside were measured by filters on nine stages Andersen air sampler. The average concentration of TSP at inside was 657.57 $\mu$g/m$^3$, which appeared about 9.2 times as high as that of 71.47 $\mu$g/m$^3$ at outside. The decrease effect caused by using new tunnel was 31.2%. As a result of correlation analysis between concentration of TSP at inside of Hwasoon Nulitjae tunnel and that at outside, correlation coefficient was 0.713. The average concentrations of SO$_4^{2-}$ , NO$_3^-$, CI$^-$ were 43.02 $\mu$g/m$^3$, 19.86 $\mu$g/m$^3$, 4.96 $\mu$g/m$^3$, those of NH$_4^+$, Na$^+$, K$^+$ 1.42 $\mu$g/m$^3$, 4.45 $\mu$g/m$^3$, 2.89 $\mu$g/m$^3$ and those of Ca$^{2+}$, Mg$^{2+}$, Pb$^{2+}$ 3.92 $\mu$g/m$^3$, 2.27 $\mu$g/m$^3$. 1.52 $\mu$g/m$^3$, respectively. It was estimated that mass fraction rate of respirable particle at inside was about 84.54% of aerosol. The average concentration of suspended particle to be collected by Andersen sampler was 478.90 $\mu$g/m$^3$, this was about 72.8% of that by high volume air sampler.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.777-784
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• 2005

The first flush phenomenon is defined as the initial period of road runoff during which the concentration of pollutants was significantly high. Road runoff contains significant loads of micro-particles, heavy metals and organic constituents. There were two major objectives of this study. The first objective was to characterize the road runoff. The second objective was to measure and evaluate particle sire distribution of the road runoff, Stormwater runoff was monitored on two sites of four lane road areas along with traffic volume. A total six storm events were monitored to characterize the road runoff. The quantity of road runoff and quality constituents, including chemical oxygen demand ($COD_{Cr}$), suspended solids(SS), total Kjeldahl nitrogen (TKN), ortho-phosphorus ($PO_4-P$), total phosphorus(TP), heavy metals and particle size distribution were analyzed. The results indicate that the concentration of SS, $COD_{Cr}$, TKN and TP ranges were $45{\sim}2,396\;mg/L$, $40{\sim}931\;mg/L$, $0.1{\sim}19.6\;mg/L$, and $0.2{\sim}25.1\;mg/L$, respectively. The results of the regression analysis between SS and the others constituents shows that $COD_{Cr}$, TP, Cu, Pb were highly correlated. And the results showed that the mean range of particle size and uniformity coefficient for road runoff were $6.7{\sim}23.4{\mu}$ and $6.4{\sim}10.2$, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.4
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• pp.214-219
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• 2017

We analyzed the water quality of first flush and rainfall runoff from a building rooftop, and investigated the removal of suspended solids (SS) in first flush using various media to develop a first flush filtration system. Particle size distribution exhibited most of particles in first flush from the rooftop ranged from 10 to 30 ${\mu}m$. SS concentrations maxed in 10~20 min and decreased afterwards. Dissolved organics and inorganic materials in runoff also showed highest levels in first flush (10 min). Filtration tests using anthracite (AC), polyurethane (PU), polypropylene (PP) showed about 50% of SS removal during the first 10 min operation, but the removal rates dramatically decreased after 20 min of filtration. Based upon the results from rinse and run cycle tests, only AC could achieve nice cycles without distinct decease of SS removal. SS removal rates increased with higher depth of media bed and lower flowrate. The system achieved over 50% of SS removal with a media depth of 30 cm and flowrate < 12 L/min.

• The Journal of the Korea Contents Association
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• v.15 no.8
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• pp.544-555
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• 2015

This study aims to derivate of the relationship and rating curve for the flow discharge-total sediment using the measured field data from the main points of small-medium stream reaches in agrarian basin. The total sediment of measured data are obtained by bed load added to suspended load which analyzed using the particle size distribution curve of sieve test and the dry or the filtration method from the collected samples by samplers (DH-48, D-74 and BLH-84, BL-84) at the stream bed and the depth-averaged concentration, respectively. These field data had been collected from August 2012 to September 2014 at the seven measuring stations of the national-local channel reaches of the four study streams in the Nonsan river systems of agrarian basin. As a result, the relationships and the rating curve for the flow discharge-total sediment are derived as a function pattern of power law by analyzing on a distribution characteristic of the database set and it will be used as a useful tool to analyze erosion, deposition, and transportation in theoretical research as well as in practical application of the hydraulic sedimentation engineering.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.235-241
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• 2004

The dissolved air flotation (DAF) process has been widely used for removing suspended solids with low density in water. It has been known as measuring the size of microbubbles precisely which move upward rapidly in contact zone is difficult. In this study particle counter monitoring (PCM) method is used to measure the rising microbubble after injection from a nozzle. Size and distribution curve of microbubbles are evaluated at different conditions such as pressure drop at intermediate valve, length of pipeline between saturation tank and nozzle and low pressure. And the efficiency is also checked when it collides with different size floc. The experimental results show the following fact. As the final pressure drop occurred closer to a nozzle, the bubble size became smaller. And small bubble collides with large floc as well as small one because of its physical characteristic. However large bubble collides well with large floc rather than small one since hydrodynamic flow in streamline interferes to collide between two. With performing computational process by mathematical model we have analyzed and verified the size effect between bubble and floc. Collision efficiency is the highest when P/B ratio shows in the range of 0.75 < P/B ratio ($R_{particle/Rbubble}$) < 2.0.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.255-260
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• 1993

The Enterobacter cloacae biofilms developed on slide glasses and galvanized-iron coupons were applied to test the attached bacterial resistance to chlorination. The chlorine resistances of biofilm bacteria grown on the slide glasses and galvanized-iron coupons were 14 and 480 times that of the suspended bacteria, respectively. The chlorine resistance of particleattached bacterial populations was 48 times that of suspended bacterial populations. The biofilm bacterial densities developed on the slide glasses and galvanized-iron coupons which were immersed in the flowing tap water for 75 days were $4.75 {\times} 10^{4}$ and $1.12 {\times} 10^5 cfu/cm^{2}$ It is concluded that main mechanisms of enteric or HPC bacterial resistance to chlorination in tap waters are bacterial attachment or . adsorption to particles or bacterial aggregations and formation of biofilms on the inner wall of distribution systems by escaped bacteria from chlorination in water treatment processes, which results in bacterial regrowth in water distribution systems.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.3
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• pp.229-236
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• 1998

Visibility is a good indicator of comprehensive alto quality. The prevailing visibility in Seoul is no better than the past although the average concentration of SO2 and TSP (total suspended particulate) has decreased quite significantly in the past decade, owing to the government efforts to reduce the emission. Then, a question arises why visibility has not been improved. In order to answer this question we have investigated which components of air pollutants are most responsible for the visibility degradation in Seoul. Analysis on the visibility vs the aerosol sixte distribution measured by an optical particle counter shows that the particles of the size interval between 0.5mm and 2.5mm are most responsible for the visibility degradation. Among the criteria air Pollutants, NOB concentration is found to be moot responsible, rather than PM10. ton analysis of the particulate collected by a high volume sampler shows that the nitrate component increases more significantly than other ions when visibility becomes very poor. Therefore, we conclude that the major causes of visibility degradation in Seoul are the increase of NOB, nitrates and the particles of the size range between 0.5mm and 2.5mm.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.12
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• pp.1353-1359
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• 2007

Water quality constituents, and particle size distributions were characterized in urban bridge road runoff, Bridge road runoff contains significant loads of micro-particles, heavy metals and organic constituents. Bridge road runoff was monitored on four sites of four and six lanes bridge road areas along with traffic volume. A total seven storm events were monitored to characterize the bridge road runoff. The quantity of road runoff and quality constituents, including chemical oxygen demand(COD), suspended solids(SS), total nitrogen(T-N), ortho-phosphorus$(PO_4-P)$, total phosphorus(T-P), and particle size distribution were analyzed. The results indicate that the concentrations of SS, COD, T-N and T-P ranges were $35\sim2,390$ mg/L, $40\sim1,274$ mg/L, $0.03\sim21.25$ mg/L, and $0.05\sim4.58$ mg/L, respectively. And the results showed that the mean range of particle size and $D_{90}$ for bridge road runoff were $4.75\sim14.05{\mu}m$ and $17.33\sim58.15{\mu}m$, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.1
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• pp.1-9
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• 2009

Distribution characteristics of organophosphorous pesticides (OPs) were studied over the period from May to September, 2006 in Asan Bay, Korea. During the study period, 28 kinds of organophosphorous pesticides dissolved in surface water and adsorbed on suspended particle were measured. In the surface water, the dominant OPs were IBP and DDVP, and the concentration were in the ranges from not detected to 2014.4 ng/L for IBP and 3.2 to 696.3 ng/L for DDVP. The highest concentrations of OPs in the surface waters in Asan Bay appeared in July and August showing that seasonal distributions of OPs depend on application time and precipitation. The concentrations of OPs generally decreased with the increase of distance from the mouth of Asan Bay, implying progressive dilution of pesticides in the estuarine system. OPs residue in Asan Bay was relatively higher than in other area of Korea. The concentrations of the observed OPs concentrations did not exceed the seawater quality standard of Korea. DDVP, IBP, Diazinon, Phorate, Azinphos ethyl and Chlorfenvinfos had higher adsorption capacity onto suspended particle than the other OPs. In the study area, adsorption coefficients $(K_d)$ of OPs were closely related to the Log $K_ow$ of each compound.

• Journal of Environmental Science International
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• v.23 no.2
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• pp.275-289
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• 2014

Asian dust (or yellow sand) occurring mainly in spring in East Asia is affected by the distribution of weather systems. This study was performed to investigate the characteristics of suspended particulate for Asian dust at Busan, Korea in 20 March 2010, which was one of the extreme case for the last 10 years. There was used the data of weather chart, satellite, automatic weather system (AWS), $PM_{10}$, laser particle counter (LPC), and backward trajectories model. In synoptically, the high pressure was located in the northwestern part and low pressure was located in the northeastern part of Korea. The strong westerly winds from surface to upper layer makes it possible to move air masses rapidly. Air masses passing through Gobi Desert in Mongolia and Inner Mongolia plateau covered the entire Korean peninsula. As the results of aerosol analysis, $PM_{10}$ concentration at Gudeok mountain in Busan was recorded $2,344{\mu}g/m^3$ in 2300 LST 20 March 2010 and their concentration was markedly increased at coarse mode particle. In surface condition, westerly wind about 3 ~ 5 m/s was dominant and small particles of $0.3{\sim}0.5{\mu}m$ were distributed on the whole. In heavy metal components analysis, the elements from the land was predominated.